EPPS, La. (AP) — Centimeter by agonizing centimeter, Leah Sellers uses a miniature trowel to scrape away thousands of years of history contained in a small 2-meter-by-1-meter rectangular hole.

Kneeling, Sellers looks intently into the 2-foot-deep hole for the slightest color variations in the soil. If Sellers — along with more than a dozen fellow geology students from the University of Louisiana at Monroe and Mississippi State University — finds lighter colored soil in the red clay, it could signal her first geological find and the most significant discovery at the Poverty Point Commemorative area in decades.

The students are part of a joint project between the universities to excavate an area of the Poverty Point State Historic Site previously believed to be devoid of any significant features.

Poverty Point is one of the most significant archeological sites in the western hemisphere. It dates back from 1800 to 1400 B.C.

Scientists using state-of-the-art technology called magnetic gradiometry have detected small variations in the magnetic field and provided the universities with maps indicating the presence of earthen circles 80 to 160 feet wide beneath the surface of the ground.

"What we want to do here this month is to examine those circles and find out what is causing those kinds of differences in the magnetic field and whether they are structures," said Diana Greenlee, Poverty Point Station archeologist and ULM geosciences faculty member. "It's very exciting."

Central construction of the site consists of six rows of concentric ridges, which at one time were 5-feet high. The five aisles and six sections of ridges form a partial octagon and the diameter of the outermost ridges measures three-quarters of a mile.

It is thought these ridges served as the foundations for dwellings.

For years, scientists have hypothesized that the plaza area of the site — near the spot where the park's visitor center now stands — was used as a community gathering place because it has yielded very few artifacts.

However, about seven years ago, Greenlee said archeologists Michael Hargrave and Burly Clay began mapping the entire site with magnetic gradiometers, a form of ground-penetrating technology that provides scientists with an opportunity to look for magnetic variations in areas where ancient soils were disturbed.

"Those variations are underground, so they can develop a map that shows where there are perturbations in the magnetic field and they have identified several large circles in the plaza area, which is pretty unusual," Greenlee said. "We had no idea that they were there."

The use of the magnetic gradiometers to find possible clues beneath the surface allows excavations of the area to be pinpointed, reducing the amount of damage to the site.

Dirt that is taken from the four areas where the excavations are taking place is sifted for artifacts, dried and placed back in the holes.

"With limited testing in the plaza, we haven't found any features that have suggested activities," said park manager Dennis LaBatt. "By nature, you wonder what they were doing in the plaza, it's really exciting in that these features on a much larger scale appear to be great big circles,"

LaBatt theorizes that the inhabitants may have used the circles to, in a sense, direct traffic into the area from Bayou Macon. Scientists already know that a sloped area leading from the bayou to the site was a major access point.

Evan Peacock, associate professor of anthropology at Mississippi State University, said data gained from the excavation could take months to sift through. The excavation project has been planned for more than year.

"Poverty Point is easily one of the most important archeological sites in North America and one of the most important sites in the world because of its scale for hunters and gatherers," Peacock said. "Obviously, it's a privilege to be here.

"We're hitting pristine archeology from 3,000-plus years ago. We're breaking new ground, there's no question about that. Finding those features was a complete surprise."

Earlier in the week the excavations began to reveal what may have been the first signs of the circular structures just over a foot below the ground's surface.

And as a future archeologist, Sellers said participation in such an important excavation is thrilling, even though she spent the better part of four days crouched uncomfortably over a hole in a grassy field.

"I thought it was going to be pretty mundane, but it turned out to be something pretty cool," Sellers said. "You can't go finding mummies on your first dig."

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Information from: The News-Star, http://www.thenewsstar.com